This invention relates to timing controllers used to turn on and turn off appliances (lamps usually) at selected times of the day. More specifically, the type of timing controller disclosed herein "learns" when the lamp is turned on and off during the first day and thereafter automatically turns the lamp on and off at the same times each succeeding day.
U.S. Pat. No. 4,349,748 to Goldstein et al. discloses such a device. In this patent, a lamp is coupled in series with the AC power supply and an electronic power switch. A sensor is coupled across the power switch and develops control signals during successive operation of the lamp pull chain. A control circuit renders the power switch conductive to turn the lamp on, or nonconductive to turn the lamp off, depending upon operation of the pull chain. The device includes its own, internal button that successively operates the power switch between its conductive and nonconductive states. It operates the control circuit the same way as the control signals from the sensor.
A slide switch is used to set the timer system into one of three modes: timer-off, timer-on, and reset. When the slide switch is in the timer-off condition, the lamp is operated by the pull chain or by the device's internal button. When the slide switch is in the timer-on condition, the control circuit will operate the power switch in accordance with the programming information in a storage device.
Programming of the timer system, by inserting markers in the storage locations of the storage device, is effected in two ways, fast programming and real-time programming. The fast-programming facet is not pertinent to the present application.
To place the timer system in its real-time programming mode, the slide switch is first moved to the reset position and then moved to the timer-on or timer-off position. Whenever the lamp is turned on or off by using the device's internal button during the next twenty-four hours, an on or off marker, as the case may be, is set automatically. The markers are delivered to storage locations of the storage device respectively corresponding to ninety-six intervals (four fifteen-minute intervals during a twenty-four hour period). The patent mentions in passing that random access memory (RAM) is possible. In the main embodiment, programming is only effected by operation of the device's internal button and not by operation of the lamp's pull chain.
When the slide switch is in the timer-off position, operation of the device's internal button or the lamp chain will operate the lamp, and the lamp will not be automatically controlled.
A second embodiment, depicted in FIG. 10, permits programming by operation of the lamp's pull chain. However, in this embodiment, the pull chain must be pulled twice in order to operate the lamp due to the hardware construction of the timer controller disclosed in this patent.
In the event of a power failure, and the resumption of power, the program in the Goldstein et al. controller will have been lost and the user will not have known about it.